July 4, 2008

Asparagus on Mars? Soil May Be Suited to It

by ssavage

By AARON MACKEY

A historic chemistry test of Mars' arctic surface suggests the red planet is capable of supporting plants and microscopic life, though scientists with the UA-led Phoenix Mars lander were careful to qualify their initial findings Thursday.

At the least, though, the test shows that Mars' arctic dirt is a lot like fertile soil in people's backyards and could be well- suited to grow such vegetables as asparagus.

Calling it the first-ever wet chemistry test of another planet's surface, elated mission scientists said initial findings indicate the soil has the ingredients necessary for plant growth.

The soil around the spacecraft has relatively low acidity and contains several plant-nourishing minerals, including magnesium, sodium and potassium, according to test results.

But scientists aren't going to be planting seeds on Mars anytime soon.

Given its extreme weather, thin atmosphere and other factors, the prospect of growing vegetables on the planet's surface is unlikely unless the growing environment could be protected and regulated, said Sam Kounaves, the lead scientist for Phoenix's wet chemistry lab.

But plant life or tiny organisms could exist just below the surface, said Kounaves, a chemistry professor from Tufts University.

"We have found what appear to be the requirements to support life," he said during a press conference on Thursday.

The crucial experiment is essential to helping scientists answer questions about whether Mars has or ever had a climate suitable for life, which is one of Phoenix's goal's.

"It's a huge step forward," said Michael Hecht, the lead scientist for the Microscopy, Electrochemistry and Conductivity Analyzer, or MECA.

"The experiment wasn't just for seeing what plants can grow, but the nature of soil and what microbes might live in it."

Launched last summer, Phoenix traveled more than 420 million miles before it touched down on Mars during Memorial Day weekend. The day-to-day science research is being conducted by the UA, which became the first public university to lead a NASA mission to Mars.

The results from the chemistry experiment also could help scientists narrow a debate about the composition of Mars' soil, as many have predicted it would be extremely caustic or unable to support life, said Hecht, who is from the Jet Propulsion Laboratory.

Though Kounaves emphasized that the test results are preliminary, the experiment shows that the soil around the lander wouldn't kill plants or microscopic organisms.

"There's nothing about the soil that would preclude life," he said. "It's very friendly."

Scientists on Thursday also discussed the preliminary results of another experiment, in which a soil sample was baked to 1,800 degrees Fahrenheit.

The sample contained carbon dioxide gas as well as water vapor, said William Boynton, a lead scientist on the Thermal and Evolved Gas Analyzer, or TEGA.

Because the water vapor was released at high temperatures, it's unlikely that it came from frozen water in Mars' surface.

The water molecules found by the experiment probably vaporized after substances they were attached to were burned up by TEGA's oven, said Boynton, who is from the University of Arizona.

Though the results were expected, Boynton said they help answer some fundamental questions about Mars.

"The soil clearly has interacted with water in the past," he said. "We don't know if that interaction occurred in this area or happened elsewhere."

More concrete results from both the chemistry test and the TEGA oven are expected in the coming weeks, after mission officials have a better chance to analyze the data.

Roughly one-third of the way through its planned mission, Phoenix has delivered unprecedented scientific information about Mars, said Leslie Tamppari, one of the mission's lead scientists.

Besides the latest experiments, the lander has measured atmospheric and weather data daily and provided scientists with visual proof that frozen water exists just below the surface, Tamppari said.

The lander also has taken more than 900 pictures of its surroundings and is working on piecing together a high-resolution color panorama of the landing site, she said.

With Phoenix just scratching at the surface of Mars - both literally and figuratively - much work remains, Tamppari said.

"We've gotten some good first samples to all of our experiments, and we have trenches dug," she said. "Now we're just going to continue digging."

On StarNet: For more Mars news and videos, visit azstarnet.com/ science